Table 1.
Chronotype subgroups according to completion of the Munich ChronoType Questionnaire for Shift-Workers
| Items | Evening chronotype | Morning chronotype | p value |
|---|---|---|---|
| Prevalence | 35 (36.46 %) | 61 (63.54 %) | N.A. |
| Age (years) | 43.85 ± 2.05 | 40.70 ± 10.56 | 0.1846 |
| Sex (female) | 25 (71.34 %) | 46 (75.41 %) | 0.6727 |
| Body mass index | 23.78 ± 3.24) | 24.25 ± 4.82 | 0.6034 |
| Children at home aged <12 years | 5 (14.29 %) | 23 (37.70 %) | 0.0148* |
| Married or living together | 24 (68.57 %) | 51 (83.61 %) | 0.0880 |
| Length of work week (days) | 4.01 ± 0.64 | 3.96 ± 0.71 | 0.7053 |
| Night shift experience (years) | 23.20 ± 13.30 | 19.07 ± 11.39 | 0.1117 |
| Night shifts per month | 5.54 ± 2.52 | 5.26 ± 1.89 | 0.5379 |
| Consecutive night shifts | 3.34 ± 0.91 | 3.43 ± 0.99 | 0.6834 |
| Sleep shortly before night shift | 8 (22.86 %) | 32 (52.46 %) | 0.0043* |
| Sleep shortly after night shift | 14 (40 %) | 18 (29.51 %) | 0.2989 |
| Nap after day shift | 10 (28.57 %) | 12 (19.67 %)a | 0.3231 |
| Nap when working the night shift | 13 (37.14 %) | 25 (40.96 %)a | 0.7146 |
| Nap on free day | 6 (17.14 %) | 16 (26.23 %) | 0.3130 |
Data are presented as the mean ± standard error (SE) or as the percentage, where appropriate
N.A., Not applicable
* p ≤ 0.05
aThe occurrence of napping while working night shifts was significantly higher than that after a day shift at p < 0.05 (paired t test)